Towards an optimised VLSI design algorithm for the constant matrix multiplication problem

The efficient design of multiplierless implementations of constant matrix multipliers is challenged by the huge solution search spaces even for small scale problems. Previous approaches tend to use hill-climbing algorithms risking sub-optimal results. The proposed algorithm avoids this by exploring parallel solutions. The computational complexity is tackled by modelling the problem in a format amenable to genetic programming and hardware acceleration. Results show an improvement on state of the art algorithms with future potential for even greater savings

A low complexity hardware architecture for motion estimation

This paper tackles the problem of accelerating motion estimation for video processing. A novel architecture using binary data is proposed, which attempts to reduce power consumption. The solution exploits redundant operations in the sum of absolute differences (SAD) calculation, by a mechanism known as early termination. Further data redundancies are exploited by using a run length coding addressing scheme, where access to pixels which do not contribute to the final SAD value is minimised. By using these two techniques operations and memory accesses are reduced by 93.29% and 69.17% respectively relative to a systolic array implementation

FPGA-based conformance testing and system prototyping of an MPEG-4 SA-DCT hardware accelerator

Two FPGA implementations of a shape adaptive discrete cosine transform (SA-DCT) accelerator are presented in this paper: one PCI-based and the other AMBA-based. The former is used for conformance testing with the MPEG-4 standard requirements. The latter is an alternative platform for system prototyping and has an architecture more representative of a mobile device. The proposed accelerator meets real time constraints on both platforms with a gate count of approximately 40k, and outperforms the optimised reference software implementation by 20/spl times/. It is estimated that the accelerator consumes 250mW on a Virtex-E FPGA and 79mW on a Virtex-II FPGA in the worst case scenario

Efficient hardware architectures for MPEG-4 core profile

Efficient hardware acceleration architectures are proposed for the most demandingMPEG-4 core profile algorithms, namely; texture motion estimation (TME), binary motion estimation (BME)and the shape adaptive discrete cosine transform (SA-DCT). The proposed ME designs may also be used for H.264, since both architectures can handle variable block sizes. Both ME architectures employ early termination techniques that reduce latency and save needless memory accesses and power consumption. They also use a pixel subsampling technique to facilitate parallelism, while balancing the computational load. The BME datapath also saves operations by using Run Length Coded (RLC) pixel addressing. The SA-DCT module has a re-configuring multiplier-less serial datapath using adders and multiplexers only to improve area and power. The SA-DCT packing steps are done using a minimal switching addressing scheme with guarded evaluation. All three modules have been synthesised targeting the WildCard-II FPGA benchmarking platform adopted by the MPEG-4 Part9 reference hardware group

Low power techniques for video compression

This paper gives an overview of low-power techniques proposed in the literature for mobile multimedia and Internet applications. Exploitable aspects are discussed in the behavior of different video compression tools. These power-efficient solutions are then classified by synthesis domain and level of abstraction. As this paper is meant to be a starting point for further research in the area, a lowpower hardware & software co-design methodology is outlined in the end as a possible scenario for video-codec-on-a-chip implementations on future mobile multimedia platforms

Hardware acceleration architectures for MPEG-Based mobile video platforms: a brief overview

This paper presents a brief overview of past and current hardware acceleration (HwA) approaches that have been proposed for the most computationally intensive compression tools of the MPEG-4 standard. These approaches are classified based on their historical evolution and architectural approach. An analysis of both evolutionary and functional classifications is carried out in order to speculate on the possible trends of the HwA architectures to be employed in mobile video platforms

Suppression of epithelial folding at actomyosin-enriched compartment boundaries downstream of Wingless signalling

Epithelial folding shapes embryos and tissues during development. Here, we investigate the coupling between epithelial folding and actomyosin-enriched compartmental boundaries. The mechanistic relationship between the two is unclear, because actomyosin-enriched boundaries are not necessarily associated with folds. Also, some cases of epithelial folding occur independently of actomyosin contractility. We investigated the shallow folds called parasegment grooves that form at boundaries between anterior and posterior compartments in the early Drosophila embryo. We demonstrate that formation of these folds requires the presence of an actomyosin enrichment along the boundary cell-cell contacts. These enrichments, which require Wingless signalling, increase interfacial tension not only at the level of the adherens junctions but also along the lateral surfaces. We find that epithelial folding is normally under inhibitory control because different genetic manipulations, including depletion of the Myosin II phosphatase Flapwing, increase the depth of folds at boundaries. Fold depth correlates with the levels of Bazooka (Baz), the Par-3 homologue, along the boundary cell-cell contacts. Moreover, Wingless and Hedgehog signalling have opposite effects on fold depth at the boundary that correlate with changes in Baz planar polarity.This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) [BB/J010278/1] and the Wellcome Trust [099234/Z/12/Z to B.S.; 099130/Z/12/Z to CAIC]. J.M.U. was supported by a Postdoctoral Fellowship [I-D+i 2008-2011] from Ministerio de Educación, Cultura y Deporte (Spanish Ministry of Education), E.S. by a University of Cambridge Herchel Smith Postdoctoral Fellowship and L.M. by an Engineering and Physical Sciences Research Council (EPSRC) Research Software Engineer Fellowship. Deposited in PMC for immediate release

Studies Regarding the Increase in Hydrophilicity of Some Textile Fabrics through Treatment by Cold Plasma and Grafting with Vinyl Monomers

The polyamide and polyester fabrics have been treated by glow discharge plasma and grafted with 2- hydroxyethylmethacrylate (HEMA) in order to increase the hydrophilicity and to improve the soil release properties. The plasma treatments were carried out at different exposure times. Grafting was obtained with gaseous HEMA and with alcohol or aqueous solution of HEMA at different concentrations. The physical and chemical surface changes were studied using scanning electron microscopy, infrared spectroscopy, colour measurements. The hydrophilicity was assessed through the absorption time of a water drop and the soil removal through washing by remission values